Non-Mopar: NEED HELP- 1995 Ford F-250 Diesel

the guys with the oil pressure are completely dead on. theres also an oil galley plug in the block behind the front cover that likes to crap out and bypass pressure, causing this issue. also, the HEUI injectors wiring harness is integrated with the valve cover gaskets, and are also notorious for falling apart, realize too before you go jank around wires to see if itll fire, those injectors run on some serious power and they will make a spark plug jolt feel like a picnic. if the oil hasnt been changed in forever, change it. those engines have 2 oil pumps, a low pressure pump for the engine bearings, and a high pressure pump for the injectors exclusively, these have been known to fail as well. Also, this ULSD fuel plays hell with any diesel, the lack of sulphur essentially removed most lubrication that was relied upon to make the system live, so worst case scenario it ate an injection pump. Best of luck.